DIPLOMATIC workers in Britain have escaped prosecution for almost 90 crimes over a six year period, including human trafficking and sexual assault, it has been claimed.

A new TV documentary will reveal how foreign embassy staff have used diplomatic immunity to dodge numerous investigations, as well as boast of using diplomatic bags to smuggle items such as gold and diamonds across UK borders.

The shock investigation has led one former diplomat to claim the system is out of control.

Of the countries whose diplomats allegedly committed the crimes, Saudi Arabia tops the list with 11 alleged offences, followed by Kazakhstan and Russia with five, Cameroon with four and the Ivory Coast and Ghana with three each.

The offences have been uncovered by ITV’s Exposure programme, which examined Foreign Office statistics on alleged offences committed by diplomats between 2007 and 2012.

Speaking on Exposure: Inside The Diplomatic Bag, which airs at 10.35pm tonight, former diplomat Eamon Delaney said: "There’s no need for so many diplomats and so many staff of embassies to walk around with immunity and with diplomatic passports: it’s an indulgence, it’s outdated, and it is a license to abuse."

Mr Delaney says during his time as a diplomat he was aware of diplomatic bags being used by other countries to transport illegal items: "Illicitly it was used to send soft drugs, cannabis, marijuana, certain art objects that shouldn’t have been moved out of the country.

"I would know of situations known to others where more serious items like such as weapons, explosives have been transferred by counties in the Middle East or Africa and they’re moved to European settings where they could be used for activities which were really sinister."

Exposure is on ITV1 tonight [ITV EXPOSURE]

Most alleged offences related to driving, but others included sexual assault, human trafficking, actual bodily harm, threatening to kill and robbery. The statistics show that of the 11 offences allegedly committed by Saudi diplomats, two concern human trafficking while one alleges sexual assault.

Diplomats from foreign countries in Britain qualify for immunity from prosecution for trivial charges to even the most serious crimes.

Last year, it was revealed foreign diplomats are refusing to pay London's Congestion Charge, racking up £74million in unpaid fines.

The Saudi embassy told Exposure that serious action is taken against any diplomat found to have broken UK laws.

The programme also contains undercover footage of Nigerian High Commission worker Alfa Abutu claiming he could use the diplomatic bag - which is immune from search by officials when crossing borders - to illegally smuggle art, cash, gold and diamonds out of the country through "any airport".

This is despite the fact that Mr Abutu, because he is an embassy worker rather than part of the diplomatic corps, does not have diplomatic immunity and has no access to the diplomatic bag.

When asked to comment on Exposure’s findings, Mr Abutu denied any wrongdoing and said he’s never been involved in criminal activities.

He said he is local staff, not a diplomat, doesn’t have diplomatic immunity and couldn’t have assisted the Exposure team to move an item. He said he believed our undercover reporter was not genuine but decided to play along with him.

Following the revelations, the Nigeria High Commission immediately suspended Mr Abutu from his position in the Accounts Department.

The Commission told Exposure that Mr Abutu "tried to fool investigators into believing that he is [a diplomat] for personal financial gain", and it utterly condemns Mr Abutu's conduct, which was entirely personal and nothing to do with them.

After viewing the undercover footage, Labour MP Fiona Mactaggart - who has lobbied on the issue of diplomatic staff who abuse their positions in Britain - described Mr Abutu’s claims as "really shocking".

She said: "Diplomatic channels are necessary in order to move secrets, in order to protect diplomats in countries which don’t respect the rule of law in the way that Britain does – and yet that means that they can be abused in this way."

A Foreign Office spokesman said the department takes a "pro-active approach" to remind the embassy staff of their legal obligations, and the number of alleged serious and significant offences committed by diplomatic staff in the UK remains low.

He said: “We take a firm line with those who break the law. The police investigate incidents in which the law has allegedly been broken by those entitled to immunity and report the results to us. We take all allegations of illegal activity seriously and act on all information we receive.

"When advised of an alleged offence, we always raise the matter with the mission concerned, seeking waivers of immunity when requested to do so by the police or other law enforcement agencies.

"For the most serious alleged offences – those that could, upon conviction, attract a sentence of 12 months or more; drink driving and driving without insurance – we seek the immediate withdrawal of the diplomat or issue a final warning as appropriate."